Our objective is to gain further understanding of the regulatory features of the utilization of glycerol and sn-glycerol 3-phosphate (G3P) by bacteria at genetic and enzymatic levels. The principal investigations will be on: 1) the control in Escherichia coli of the activities of the transport proteins through interactions with other permeation systems, especially those for carbohydrates that are used in preference to glycerol and G3P; 2) the regulation in the synthesis and operation of two membrane associated and flavin-dependent G3P dehydrogenases by respiratory conditions or elements; 3) the nature of the respiratory control for the synthesis of fumarate reductase; 4) the relative functional merits of catabolic glycerol pathways initiated by dehydrogenation versus those initiated by phosphorylation; and 5) the mechanism of the specific inactivation in Klebsiella aerogenes of the inducible glycerol dehydrogenase following the shift from anaerobic to aerobic growth on glycerol. The studies will be carried out with the aid of mutant analysis, both for locating the relevant genetic loci and for characterizing their function. The isolation and characterization of the membrane bound proteins will also be an important part of the methodology.